The present disclosure relates to an imaging apparatus, an image processing apparatus, an image processing method, and a program. More particularly, the disclosure relates to an imaging apparatus, an image processing apparatus, an image processing method, and a program capable of correcting images captured by the imaging apparatus.
In recent years, imaging apparatuses such as a still camera, a video camera, a single lens reflex camera, a camera built-in to a mobile device, a camera built-in to a PC are being miniaturized, and their costs and weights are being reduced. However, these miniaturized and light-weight cameras have many design limitations in the optical systems such as lenses. As a result, image degradation caused by, for example, lens aberration and the like may easily occur.
Lens distortion aberration (distortion) is a phenomenon that can easily occur as the zoom ratio of the camera increases. There are specific examples of lens distortion aberration, for example, as follows: (a) barrel distortion by which the captured image is circularly outwardly skewed like a barrel, (b) pincushion distortion by which four corners of the image are extracted and stretched like a pincushion, and (c) a mixture of both distortion types, for example, such as lens distortion aberration or mustache distortion.
Distortion aberration can be prevented by improving precision of the lens design to some extent, but it is difficult to remove it completely. Particularly, in the miniaturized, light-weight, and low-cost camera as described above, it is realistically difficult to use lenses fabricated with high precision. In order to address such a problem, recently, cameras having a function of correcting distortion of the captured image by performing geometrical transformation through image processing are being developed.
In addition, another problem accompanying miniaturization and increasing light-weightness of cameras is that stability of the captured image is deteriorated by user's hand-vibration or vibration (in a vehicle and the like) of the imaging condition. Techniques for suppressing such a vibration component representatively include a technique of suppressing vibration by guiding light into a direction capable of optically canceling out the vibration in a lens portion or an image sensor portion (optical correction), and a technique of reading the image data obtained after the imaging by canceling out the data that corresponds to the vibration (electronic correction). In both types of correction techniques, the vibration component is divided into translation vectors, for example, using two axes in the horizontal and vertical directions (X and Y directions, respectively), and each correction amount is computed. However, in practice, hand-vibration further has a rotational vector component in addition to the translation vector in many cases. Therefore, it is difficult to remove this rotational hand-vibration using the translating correction in the X and Y directions.
Meanwhile, a human being can stereoscopically view an object because both eyes are separated at a certain interval, by which the object is viewed from different directions, and spatially offset images are focused on each retina. That is, a stereoscopic feeling is recognized using parallax between both eyes.
A so-called stereo camera for capturing stereoscopic images using the imaging apparatus, that is, a camera having two optical imaging channels is also based on this principle. Two different channels of images are captured as a source of the stereoscopic image.
As such, the stereo camera generates two-channel images, that is, the left-eye image and the right-eye image and stores them in a memory. The left-eye and right-eye images are alternately displayed, for example, on a 3D display. A viewer can view a stereoscopic image by wearing shutter type glasses and viewing each image with only a left eye or only a right eye. Various techniques other than the shutter type glasses technique can be employed to display 3D images.
Although a sense of depth can be perceived depending on the parallax of the captured image through the 3D display image, the stereo camera has some requirements in capturing an image to suppress viewer fatigue and realize comfortable vision. Specifically, it is necessary to adjust setting of the parallax or accurately optimize the installation position or direction of two-channel optical imaging systems for the left-eye image and the right-eye image.
Since each channel of the two-channel optical imaging system for the left-eye image and the right-eye image of the stereo camera uses an individual lens, separate lens distortion aberration is individually generated. Therefore, in order to remove distortion aberration, it is necessary to individually correct each lens.
An exemplary technique for correcting two types of images captured by the stereo camera of the related art is disclosed in, for example, Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2008-524673.
As described above, the image correction process for the image captured by a camera includes lens distortion aberration correction, translating hand-vibration correction, and rotational hand-vibration correction. Further, in the case of a stereo camera, correction is further necessary depending on many other purposes, such as parallax correction for the two-channel optical imaging system.